System and method for automatically tracking and utilizing excess material on a CNC machining system

ABSTRACT

In many manufacturing industries, off-fall or excess raw materials are often wasted as scraps. Even if the excess raw materials are later reused, they are not being used in an optimized way. The present invention discloses a system and method of profiling excess raw materials, assigning an identity to each excess raw material, storing the identity in a database, and use nesting part program techniques to identify a an excess raw material best suited for the nested part programs.

FIELD OF THE INVENTION

[0001] The present invention is in the field of maximizing use of rawmaterials in a computer numerical controlled machine manufacturingenvironment.

BACKGROUND OF THE INVENTION

[0002] It has become a common practice in furniture and cabinetmanufacturing operations to utilize Computer Numeric Controlled routersto fabricate casework components from large sheets of material, such asthose disclosed in U.S. Pat. Nos. 3,942,021 and 3,931,501. Frequently,the flat casework components for an end-product are consecutivelyprocessed from the same sheet of material. Given that differentcomponents are different in sizes and shapes, tremendously amount ofwastage could result from a lack of prior planning. Therefore, effectivematerial utilization has become a major challenge in this type ofmanufacturing method.

[0003] In some cases, a software algorithm in a machine control may beutilized to automatically arrange the positioning of component cuttingprograms in such a manner as to minimize the amount of space betweencomponent profiles, thus consuming the least amount of material from agiven sheet. This is commonly referred to as nesting. Nesting hassignificantly contributed to both the versatility and productivity offurniture and cabinet operations. However, even in a typical customcasework operation with nesting, as much as 30 to 50 percent of thefinal sheet from a production run may remain unused, thus, becomingoff-fall material or off-fall sheets. Unless this material can be usedfor another product, it will be scrapped.

SUMMARY OF THE INVENTION

[0004] The first object of the present invention is to provide asoftware system for automatically nesting a plurality of individual partsub-programs, entered into a machine control on an individual basis, toachieve the optimum placement density on a sheet of raw material formaximum material conservation.

[0005] A further object is to automatically monitor and sort theoff-fall material from a CNC cutting cycle, according to size, shape,and type, then utilize said off-fall as raw material in subsequentcutting cycles, based on an optimum nesting pattern.

BRIEF DESCRIPTION OF THE DRAWING

[0006]FIG. 1 illustrates the embodiment of a computer numeric controlledmachining system.

[0007]FIG. 2 illustrates a complete sheet of material with workpiecesub-programs nested for optimum material utilization.

[0008]FIG. 2a illustrates a piece of off-fall scrap from FIG. 2 withworkpiece sub-programs nested for optimum material utilization.

[0009]FIG. 3 is a logic-flow diagram of the rolling nesting operation.

[0010]FIG. 4 illustrates a bar-code label encoded with the identifyinginformation for a piece of off-fall.

DETAIL DESCRIPTION OF THE INVENTION

[0011] The invention disclosed herein provides a software system locatedwithin the CNC machine control, that automatically identifies and tracksoff-fall sheets according to size, shape and type. The software systemperforms nesting of individual part programs in the control, so as tooptimized usage of the off-fall sheets given their sizes, shapes andtypes.

[0012] When individual part programs are loaded into the machinecontrol, the system will either automatically nest parts ontoappropriately sized off-fall sheets that are leftovers from the previouscutting cycle, or prompt the operator as to which off-fall pieces fromprevious cutting cycles should be utilized for optimum materialutilization. The system can then nest all, or a portion of theindividual part programs into one or more individual off-fall sheets,grouping the part programs and off-fall sheets into the optimumcombination for maximum material conservation.

[0013] Referring to the drawing in FIG. 1, there is illustrated, anembodiment of a computer numeric controlled (CNC) machining system,which generally includes a base member 107, a worktable 101, a gantry, atoolhead support assembly 103, and an electric spindle, 104. The gantry,includes a pair of leg members, 106 and 111, rigidly secured at theirlower ends to the base member and a transversely disposed section 102,supported on the leg sections and spanning above the worktable. The basemember is formed of steel sections welded together to provide a rigidand stable foundation. Worktable 101 is mounted horizontally with thesurface parallel to the x and y axes plane and is adapted to bedisplaced longitudinally relative to the base member or along a y-axis.The front face of transverse section 102, is provided with a pair ofvertically spaced, transversely disposed rails 108, and 109, onto whichtoolhead support assembly 103, is mounted and displaceable transverselyor along an x-axis. Electric spindle 104, is mounted on the bottom ofthe toolhead support assembly and is adapted to be displaced verticallyby same. Each of worktable 101, toolhead support assembly 103, andelectric spindle 104, is displaceable along its respective axis by afeedscrew arrangement driven by an AC servomotor. The operation of suchservomotor is controlled by a programmable computer-numeric controller110 to provide for movement of a tool mounted on the toolhead along amotion path to perform a work function such as routing, shaping,drilling and the like on a workpiece mounted to the worktable. Insteadof the worktable being displaceable and the gantry being stationary asdescribed, the worktable can be stationary and the gantry may bedisplaceable along the Y-axis to provide displacement between the gantryand the worktable.

[0014] In CNC panel processing operations of the present invention, itutilizes nesting software systems to distribute individual componentcutting profiles on a panel or sheet of material for optimum materialutilization. A nesting software system of the present invention utilizesa mathematical algorithm to derived numerous permutations of partplacement patterns, and then selects the pattern most favorable formaximum material conservation.

[0015] A sheet of raw material 201, with a plurality of individual partprograms representatively labeled as “a” through “i” nested thereon, isillustrated by way of an example in FIG. 2. The remainder of thematerial sheet or off-fall sheet 202 is not being utilized in thepresent cutting order and will therefore become a major portion of thewaste material. Such waste material is regarded and identified herein asoff-fall, because in reality, this material will be utilized again infuture nested cutting operations as is exemplified in FIG. 2a.

[0016] As shown by way of an example, a plurality of subprograms a, b,c, d, e and f is nested on the off-fall sheet 202 in a manner so as tomaximize the usage and minimize the wastage of the off-fall sheet 202.As can be readily seen, the representatively shown part programs a, b,c, d, e and f in FIG. 2a are indeed identical as the representativelyshown part programs a, b, c, d, e and f in FIG. 2. The nesting has beenvariously rearranged so as to best fit the profile of the off-fall sheet202. Notice that the final nesting in FIG. 2a contains two part programse. This is done to make use of the otherwise waste material defined bythe boundaries of part programs b, c and e.

[0017] The shape and area, generally referred to as a profile of theaforementioned off-fall is recorded in the memory of the machine controlby first assigning geometric values to distinctly identify the size andshape of the material, and then assigning an identifying number forfuture selection and retrieval. The type of material is also tracked andencoded in the identifying number, based on the type of materialspecified in the original prompting to load the material. The operatoralso has the capability of editing the database, manually adding orremoving off-fall sheets.

[0018] In subsequent operations, as individual workpiece programs areentered into the control or various workpiece programs are loaded intothe control, the aforementioned off-fall, along with other previouslyentered off-fall pieces, will be considered for nesting the workpieceprograms.

[0019] Referring to the logic-flow diagram of FIG. 3, cutting partprograms are entered into the CNC control for future processing, asshown in step 301. The operator selects one or more part programs to cutthe sheet stock residing on the worktable 101, as shown in step 302. Thecontrol then checks the geometry and material type of any off-fall sheetresiding on the worktable left from the preceding operation, as shown instep 303, and a determination is made as to whether this material is ofa favorable size and type for nesting a number of selected programs forthe next cutting operation, as shown in step 304. If the number ofselected cutting programs fit ideally within the boundary of theoff-fall material, the programs will be nested, as shown in step 313.However, if there is no material left on the worktable, or if theremaining off-fall material is not suitable for nesting the number ofselected cutting programs, due to inadequate sizing or wrong materialtype, the operator will be prompted to remove the off-fall material forfuture use, as shown in step 305. A database in the control or locatedelsewhere can be queried for material of suitable size, shape, and type,as shown in step 306. If any off-fall material meeting the propercriteria is identified by the database, the best available size andshape of the existing stock is selected by a computer algorithm, asshown in step 308, and the operator is prompted by the control as towhich piece of material to load onto the worktable, as shown in step309. The operator will then load the material, as shown in step 312, andthe control will proceed to nest the cutting programs, as shown in step312. If no off-fall material meeting the proper criteria is identifiedby the database, the control will use a new sheet of material, as shownin step 310. The operator will then be prompted to load a new sheet ofmaterial of the proper type, as shown in step 311. At this time, thecontrol will nest the cutting programs into the selected material piece,as shown in step 313, and the program proceeds to run, as shown in step314. After the program is completed, the machine control utilizes analgorithm to determine the geometry of the off-fall material, as shownin step 315. If the geometry of the off-fall material falls within apredetermined criteria, for example, the excess material remaining is atleast 30% of a new workpiece, the excess material remaining is at least1 foot by 2 feet, etc., as shown in step 317, an identity will beassigned to the off-fall material, as shown in step 316, and stored inthe database, as shown in step 320. The operator will then be promptedto save the off-fall material, as shown in step 321, and the off-fallmaterial will be left to remain on the worktable for the next programnesting consideration or appropriately stored for future use, as shownin step 322. If, however, the geometry of the material does not fallwithin the predetermined criteria, the operator will be prompted todiscard the material, as shown in step 318.

[0020]FIG. 4 illustrates by way of an example an identifier in the formof a bar-coded label that contains the identifying information for apiece of off-fall. This label is merely representative of a labelcontaining the identifying information stored in the control for aparticular piece of off-fall. The first set of characters 401 identifiesthe thickness of the material in millimeters. The second set ofcharacters 402 identifies the type of material. The third set ofcharacters 403 identifies the physical size and shape of the off-fall.

[0021] From the foregoing detailed description, it will be evident thatthere are a number of changes, adaptations and modifications of thepresent invention which come within the province of those persons havingordinary skill in the art to which the aforementioned inventionpertains. However, it is intended that all such variations not departingfrom the spirit of the invention be considered as within the scopethereof as limited solely by the appended claims.

I claim:
 1. A method of managing an excess material left from aworkpiece by using a computer numerical controlled machine with acontroller connected to a database, comprising a plurality of steps of:determining whether the excess material fits a predetermined sizecriterion; discarding the excess material if the excess material doesnot fit the predetermined size criterion; formulating a characteristicsprofile of the excess material if the excess material fits thepredetermined size criterion; deriving an identity encompassing thecharacteristics profile of the excess material; and storing the identityin the database.
 2. The method of claim 1, further comprising a step of:nesting a program comprising a plurality of part programs based on thecharacteristics profile.
 3. The method of claim 2, further comprising astep of: cutting the excess material based on the nested program.
 4. Themethod of claim 1, wherein the characteristics profile is formulatedimmediately after the workpiece has been cut by the computer numericalcontrolled machine.
 5. The method of claim 1, wherein thecharacteristics profile comprises a size, a shape and a type of materialof the excess material.
 6. The method of claim 2, wherein nesting of theprogram is performed immediately after the workpiece has been cut by thecomputer numerical controlled machine.
 7. The method of claim 2, whereinnesting of the program is performed after the excess material has beenloaded on a worktable of the computer numerical machine.
 8. The methodof claim 2, wherein nesting of the program is created by loading theplurality of part programs into the controller.
 9. The method of claim1, further comprising a step of: nesting a program based on a pluralityof part programs.
 10. The method of claim 9, further comprising a stepof: locating from the database a characteristics profile of an excessmaterial that is suitable for the nested program.
 11. The method ofclaim 10, further comprising a step of: loading the excess material on aworktable of the computer numerical controlled machine if thecharacteristics profile is suitable for the nested program.
 12. Themethod of claim 9, further comprising a step of: loading a new workpieceon a worktable of the computer numerical controlled machine if nocharacteristics profile is suitable for the nested program.
 13. A methodof maximizing use of an excess material of a workpiece in a computernumerical controlled machine system, comprising a plurality of steps of:a. loading one of a part program and a plurality of part programs into acontroller of the computer numerical controlled machine system; b.selecting at least one part program for cutting the workpiece; c.determining whether any off-fall remains on a worktable of the computernumerical controlled machine system.
 14. The method of claim 13, furthercomprising a step of: d. querying for an off-fall of a suitable sizefrom a database of the computer numerical controlled machine system ifthere is not any excess material remaining on the worktable.
 15. Themethod of claim 14, further comprising a step of: e. determining whetherany off-fall of suitable size, shape and type of material is located inthe database.
 16. The method of claim 15, further comprising a step of:f. selecting a new workpiece if an off-fall of suitable size, shape andtype of material is not located in the database.
 17. The method of claim16, further comprising a step of: g. prompting an operator to load a newworkpiece on the worktable.
 18. The method of claim 13, furthercomprising a step of: h. determining whether the at least one programwill nest onto an off-fall remaining on a worktable of the computercontrolled machine system.
 19. The method of claim 18, furthercomprising a step of: i. nesting the at least one program onto theoff-fall.
 20. The method of claim 19, further comprising a step of: j.cutting the off-fall based on the nested at least one program.
 21. Themethod of claim 20, further comprising a step of: k. determining acharacteristics profile of any excess material remaining from the cut.22. The method of claim 21, further comprising a step of: l. determiningwhether the excess material fits a predetermined size criterion.
 23. Themethod of claim 22, further comprising a step of: m. discarding theexcess material if it does not fit a predetermined size criterion. 24.The method of claim 23, further comprising a step of: n. assigning anidentity encompassing the characteristics profile to the excess materialif it fits a predetermined size criterion.
 25. The method of claim 24,further comprising a step of: o. storing the identity in the database.26. The method of claim 25, further comprising a step of: p. storing theexcess material.
 27. The method of claim 18, further comprising a stepof: q. removing the excess material if the at least one program does notnest onto an off-fall remaining on a worktable of the computercontrolled machine system.